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› Sylphide E conversion
12-30-2009 03:00 PM  7 years agoPost 21
Wayne Mann

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United States of America

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Hi Stan,

Yes the packs that we used this year are very good. They are Thunder Power 5s 6600. I think they are 20C batteries. The world champion Mr. Ito used them along with about 6 other guys. For F3C or contest type flying we don't need high (C) rated batteries.

The formula we use is what Castle recommended. I have several calculators for this stuff that work. It is all about finding the right gear ratio. The right gear ratio for F3C or AMA competition is one that gives you just enough head room so that you can get through your flight without the head speed starting to sag before you finished the last aerobatic maneuver. If I was to do an extra maneuver before the auto I would want the head speed to start droping off some by the end of that maneuver. I realize that this is a simple approach, but that is how some of us approach things like this so that we can more easily help other people get their machines flying properly.

I need to adjust my efficency number slightly as I am having to push my idle up throttle curve slightly so that I can get to 2000 rpm upstairs from 1890 rpm. I have several different brands of ESCs and this has worked well on all of them, but I have not played with the lower kv motors so I am not sure how my calculator will work in that range. It should be the same, but who knows.

As for the load numbers I have no idea. Dwight has done many tests with the data logger and quite frankly Dwight had his machine running before I did, by three weeks or so, so he did much of the prelimenary work figuring out the most efficent gear ratios. We are not concerned how long the batteries will hold 42 volts per say as we only care about maintaining 2000 rpm through the last maneuver. I realize that the two are directly related. Here is our throttle curves for upstairs and hover. Upstairs we are at 55% straight across for our throttle curve and we are at 30.5% in a hover which is about 1520 rpm. The Castle HV 85 is being run in the high rpm mode.

Wayne

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12-30-2009 05:20 PM  7 years agoPost 22
papatango

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Toronto, Ontario, Canada

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Nob,

Talk to David at Xera(CNCaddict on RR) about the efficiency of the 4030 vs 4035 xera's; he might recommend staying with the 4030 if your sylphide stays under 12 lbs.

Let us know what power consumption is like with the Xera, it looks like a great build.

Cheers,

Patrick

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12-30-2009 06:30 PM  7 years agoPost 23
Dr.Ben

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Richmond, VA, USA

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Wayne,

My Eagle is getting pretty creamy.

The numbers right now are 9:5:1 with a 500 kV motor. All the calculations predicted that 450 kV was about ideal, but the logger data show that headroom was going to get pretty close with that gearing. 9:3 would of course have gained me some headspeed, but with some increase in peak current d/t the taller gearing. The ICE logger data from last Sun's flying showed the motor to be running at about 92% throttle upstairs with occasional peaks to 100% under instantaneous load. RPM data show the headspeed to be constant across the entire flight. The model runs like a watch in hover at 1480 rpm. Peak hp is a bit over 3000W with 80 amp peaks. I'm surely geared a bit more to a bias of efficiency versus brute power, but since I have much more than I did with the nitro motor, I have no need for my aerobatic schedule to gear this thing for 4500-5000W peaks.

It is interesting to note that as pseudo-homage to nitro motors and governors and so forth and all their idiosyncracies, this combination is NOT happy at all typical aerobatic rpm choices. I had played a little with 1950, but the motor ran markedly rougher that way in idle up than it did at 1980, which is very good. I forgot to try setting the headspeed just in the roll condition for 2K+, since the faster the headspeed the better for rolls. 1980 is plenty for the other stuff I need to do.

On this EXII I'm building I may play with a 530 kV motor or the 9.3 gearing just to compare notes.

Ben

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

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12-30-2009 08:56 PM  7 years agoPost 24
Wayne Mann

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United States of America

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Hi Ben,

I need to get Dwight to chime in here as I have no idea what our actual throttle percentage is upstairs according to the data logger. If I drop one tooth on the engine pulley which takes me from 12.12:1 to 12.62:1 I will start to lose head speed at the end of the flight and I can tell that I have lost quite a bit of hp upstairs. I have gone the other way and went from a 25 toa 26 tooth pulley and the model runs just as good with plenty of battery to get through the flight and the hp gain is definetely noticable upstairs. But, at 12.12 it already has so much available power it is stupid. Lets put it this way it has enough power to lock up the auto clutch as it did in the last round of (C) schedule at the worlds. I have never had a Caliber 90 auto clutch lock up before. It may have been a fluke, but you never know. Coming through the last 180 turn in the (S) auto I was like; Man someone stole my MoGo. The head speed was falling faster than a love sick man hole cover.

Wayne

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12-30-2009 08:58 PM  7 years agoPost 25
Wayne Mann

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I forgot to ask Ben, what is the power like upstairs with that combo? Is it the insane power that we have with the Neu 684 kv motors or do you not have enough gear in to get it to really go? What motor are you using now?

Wayne

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12-30-2009 11:59 PM  7 years agoPost 26
Dr.Ben

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Richmond, VA, USA

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Wayne,

Right now I have a Scorpion HK4035 500 in the model. It's not geared for insane power. I pretty well have it geared to provide more power than I need for the CIII schedule and thus have some bias towards efficiency.

I have yet to completely mash on the collective for anything. For something like a RST/540 and with about 10D of pitch in the model, I'm only going to about 4/5 total pitch to make the verticals as tall as I need them to be. It'll cruise into a maneuver at sensible speed and pull vertical really well as soon as I ask it too.

I've been very cautious in sneaking up on how hard I'm pushing this model too, because the E3 won't allow me to run a top bearing support on the motor. The gears are holding up fine, but I'd prefer to sneak up on really asking the model to dig in rather than push too hard and too fast and not hear or see the warning signs of a problem before it lets go entirely. Once I get the new, stronger shaft in my motor, I'll feel that much better about turning it loose.

I pretty well know exactly what to do to the gearing to make this model go like a raped ape, but there's really no use in extracting over 4000 watts from the system when I need only a bit over 3000 to do really nice aeros with enough left under the left thumb to allow for bad wind conditions.

Now........when it gets really hot outside, the 9.3 gear may well have to go in. This winter air is of course ideal for all kinds of flying right now if you keep the packs warm before flying.

Ben

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

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12-31-2009 03:05 AM  7 years agoPost 27
Wayne Mann

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United States of America

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Hey Ben,

One last question. You must be running the ICE ESC in low speed mode? That would make since as your numbers do not add up with our calculations as we run our ESCs in high speed mode.

Wayne

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12-31-2009 03:14 AM  7 years agoPost 28
rocket_33

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Mount Pleasant, Michigan USA

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Setup For Discussion

I hope that I am not hijacking the thread but I thought I would toss up what I am thinking about the conversion on my Vibe 90. My configuration would be to stay with the 88 tooth main gear, and a 9 tooth pinion (9.78 to 1). I am looking at using a 550kv motor.

Now my question to those of you with the experience is amd I close? I would like to be around 1460 for hover and 2000 for upstairs. I am still considering what speed controller to use but am leaning towards the Jive. I am not sure if the speed controller will play a role in the decision as again I am listening, reading and learning.

Any thoughts or opinions? Any issues I may not have looked at?

Thanks

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12-31-2009 04:01 AM  7 years agoPost 29
Dr.Ben

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Richmond, VA, USA

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Nope Wayne, I'm using set RPM mode and have used gov high mode as well with the same number. Gov low will barely drive the head enough to get the model off the ground, if that.

The unloaded tach'd rpm of the model with no blades attached is pretty much what the calculators suggest, but those numbers don't directly transfer when the blades are on and the model is upstairs.

Also, as Nob commented, using a formula with 51 volts in it does not represent the real world and what the packs are doing in the air. You've got to use no more than 3.85 to get the average voltage for the flight, or really 3.7 to have the numbers on paper translate to the air AND to what the logger spits out to confirm or deny the theoretical. Here's a pic of logger data for another Freya set up https://rc.runryder.com/helicopter/...?p=4630864&i=1. His average voltage quickly drops and settles down around 3.85 V or so. CC bases all their governor rpm parameters around 3.7V per cell. The set rpm mode will warn you when you stray outside the suggested gearing vs. rpm parameters. Finally, if you read around on the other electric forums, those using CC ESC's often end up gearing taller than they would have predicted to still achieve the headspeed the calculations predicted and with suffidient headroom. I will wager that this is even more the case when those calculations are done using peak pack voltage versus nominal.

I would allow for the possibilty of a motor, battery, or ESC issue causing the disparity between your calculations and what my model is doing in the air, but the data have been largely consistent for two motors, two ESC's, and two sets of batteries.

Ben

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

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12-31-2009 05:59 AM  7 years agoPost 30
Wayne Mann

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Let me see if I can explain this better. The way Castle wants you to determine your head speed upstairs goes something like this and it works extremely well. Remove the rotor blades and tail blades. Set throttle curve for idle up to 100%. With a fully charged set of batteries run the model up and engage idle up. Use a tack to determine head speed. Take that head speed and divide it by .80 and that is your targer head speed. If the target head speed you came up with is not what you wanted then regear the model and try again. If you did come up with the right head speed adjust the throttle curves on idle up for that head speed and you are done. The .80 efficency number is a little bit on the conservative or efficent side. My target head speed is actually 1896, but I bump up the idle up curves a little bit to get me to 2000 rpm. With the schedules we flew this year I can get away with that without having the problem of head speed falling off at the end of the flight. If the flights took another minute to complete for example I would have to gear the model up slightly (add one more tooth to the pinion gear) in order to keep from loosing head speed at the end of the flight. The new schedules for next year take less time in a hover and they require less hp (watts) upstairs so I would be able to drop one tooth on the pinion probably (assuming I stayed with 10s) without running into the sagging head speed at the end of the flight condition. I hope this makes more since.

What I am also getting at is that you are actually geared more for power than you are for efficency. If I threw your engine in my model and set it up for the schedule we are flying this year with 12s power the numbers would look like this:

51 volts x 500 kv = 25500 divided by 10.8:1 = 2361 x .80 = 1888
I would then raise the throttle curve slightly to get the head speed to 2000 rpm upstairs. Now the unknowns here are the fact that the motor your running is a 10 pole motor compared to the 8 pole Neu motors. I'm not sure what effect that that would have on the equasion and I have no idea what kind of power that motor puts out. It may need to be over geared to get good power
from it.

I need to test one of these lower kv motors to see how they perform in my machines compared to the higher kv motors. I have an Xera 4035 300 kv motor in one of my AP birds, but I am thinking it might be a little bit on the weak side for this appiciation. However, it totes around my 30 pound video rig like its nothing.

If you do two extra maneuvers at the end of your schedule and by the middle of the second maneuver if your head speed has not started falling off then you are geared too tall. You are geared towards power and not efficency.

Wayne

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12-31-2009 06:25 AM  7 years agoPost 31
Wayne Mann

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United States of America

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Hi Rocket_33,

Sorry for not responding to your question already. I assume that we are talking about a contest type set up running on 12s? I think you would be closer to ideal with a 500 kv motor. I have not tested these lower kv motors yet so I am maybe not the one to get the best advice from. However, a 550 kv motor with a 9.75:1 ratio running on 12s is going to have a lot of head room built into it. With your proposed set up it is going to be hard to pull the throttle curve out enough to get to 1460 rpm on the head for hovering.

Wayne

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12-31-2009 04:27 PM  7 years agoPost 32
rocket_33

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Mount Pleasant, Michigan USA

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Thank you for your comments. I understand what you mean when you refer to having too much headroom but my concern is not being able to hit my target HS upstairs. I may have misunderstood what I have been told about the various speed controllers. I was under the impression that you don't want to run them higher than 80 percent to allow headroom for it to compensate as voltage decreases. So based on this logic is it correct that I should use the calculators to determine my headspeed at 80 percent.

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01-01-2010 03:41 PM  7 years agoPost 33
Dr.Ben

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Richmond, VA, USA

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Hi Wayne. Happy New Year.

In the course of this discussion one thing that was unclear to me was which firmware version you are now flying. At the WC and last summer in general, I believe that you and Dwight were running firmware 2.16 or maybe 2.18. They've since gone through three software revisions, each resulting in vastly improved governor fuctionality and overall efficiency. I spent about 3 hours on the phone with Clint Akins over several sessions as I was trying to come to terms with the gearing on this model. I understand what you've said about looking for the drop off after doing maybe a few extra maneuvers at the end of the flight, by the new software, especially set rpm mode, will hold headspeed until the packs pretty much have little left to give. Thus that indicator is likely not as reliable as it once was. Clint no longer uses that formula as the basis for setting up electric models, and his target throttle range for governed set up is now 85% up to the low 90's. I am rather uncomfortably setting up around flying until headroom is exhausted when the new software will do all it can to hold the headspeed until the packs have little left to give. There's too much chance off pushing pack voltage below where I want it to go with items that aren't a dime a dozen, so to speak.

Gearing the model for the most power would involve running a taller gears such that the motor is pulling harder and more resutling headroom. Peak current under load is of course higher, which is why the 3D guys see spikes of well over 100 amps and 4.5 minute flight times. The 3D guys do this all the time with their set ups and the 1915 Neu motor by gearing closer down to 9.0:1. Right now I'm at 9.5:1. Earlier this year I had done the classic 80% calculation as you describe. Based on that technique, you would expect my headspeed to end up at about 2100. It doesn't. The reason I know it doesn't is because the ICE logger tells me exactly how much the ESC is opening the "throttle" to maintain the 1980 I'm set to right now. It told me it needs 92% throttle on average to hold that headspeed, even at the start of the flight. If I gear this model even shorter such that the governor has to open the throttle even more, I might as well not use the governor at all because I'll be flying around at 100 % throttle all the time, and the head speed will fall accordingly over the flight as pack voltage drops with no headroom with which the governor can work. When you're up and flying with the ICE logger and it's telling you what the model is really doing in the air, the formula pretty much goes out the window. I based the set up on the real time data, and that data suggest that I'm running this system about as efficiently as I can with the gearing options I have available.

Ben

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

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01-02-2010 02:41 AM  7 years agoPost 34
ymuraki

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Tampa, FL

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Xera 4030

Patrick,

My Sylphide is done. All up weight with Zippy 5000 packs ended up 13.0lb (5.9kg) with 185g main blades. It's 1lb heavier (and 1 lb heavier than T700-E) than nitro version with 1/3 fuel in the tank, but it shouldn't be too bad on S-Auto.

I received Scorpion 4035-400, so I installed it and ready to go.
Outside had been nasty all day today, so I did some test without blades today.

Castle's new firmware 3.23.
High Gov mode:
Set 3% (not 30%)on Thr: Head speed 1600rpm, 85% thr: 2100rpm, 100% thr: 2350rpm.

Low Gov mode:
Thr: 80% = 1500rpm, 85%= 2045rpm, 100%=2045rpm.

Fixed RPM: <50% Set for 1470 = 1470rpm, 85% set for 2000rpm = 2000rpm, 100% & set for 2100=2025rpm.

I guess I should try Low Gov mode. I think 2045 rpm governed should do for me.

Nob

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01-02-2010 02:47 AM  7 years agoPost 35
Wayne Mann

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United States of America

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Happy New Year,

I now realize where I went wrong in my explanation of how we use the calculator. The tack test is ran with the governor mode in the CC ESC turned off. The throttle curve in idle up is at 100%. Once we run the model with no blades and tail blades and get a tack reading at 100% we then divide that number by .80 which gives us our target head speed and assuming that head speed is what we are looking for we enable the governor mode on the ESC. With the governor mode enabled we adjust the throttle curve so that the governor holds the head speed (no blades)at the target head speed and we are done. Install blades and go fly. I forgot to mention before about turning the governor mode on and off to get the set up done correctly. I think some were assuming that I was running the throttle curve at 100% with my gearing set up to give me my target head speed with 42 volts and no governor. Head speed would fall off rather rapidly. My bad.

Ben, I am still running the version of the software that we ran in Nashville, if that tells you anything. The things run so flawlessly I would be scared to try anything else. I have a hard time seeing how it could get any better.

Wayne

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01-02-2010 03:40 AM  7 years agoPost 36
Dr.Ben

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Richmond, VA, USA

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I flew some more today Wayne. I bumped the headspeed up to 2000K, and the governor is running at no less that 95% when the collective is in the model upstairs. It pegs at 100% on the pulls for aeros. The headspeed will drop to about 1910 in the rolls and briefly to 1925 during the RST. Effectively, I'm running with very slim headroom. Unless you or anyone else here can suggest otherwise, I'm thinking my gearing is a fuzz too short. I may have to try the 93t maingear. I would surmise that some of the narrow headroom is caused by the fact I was flying in just over 40D F temps, though I was making an effort to keep the packs from cold soaking completely.

In talking with Clint, the main reason that you and Dwight may want to try the newer firmware is that you could see an increase in efficiency and runtime. Obviously, you'd need to log where you are now, make the change, and then relog the same flight to compare. In some cases and set up, the increase in runtime has increased by an average of a minute or more. I agree it would be hard to ask for a sweeter running set up than you have now, but I'm also sure you wouldn't turn down a little more efficiency with all other attributes of your set up maintained.

Ben

Team Synergy Team Futaba Team Kontronik USA
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01-02-2010 04:26 AM  7 years agoPost 37
Wayne Mann

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United States of America

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Hi Ben,

I would probably not mess with the gearing until the weather warms up some. I have not flown my contest stuff in cold weather, but I have flown my AP stuff in some nasty conditions to partly nasty conditions and cold weather really effects the output from the batteries.

Wayne

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01-02-2010 04:29 AM  7 years agoPost 38
F1 Rocket

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Melbourne, Florida USA

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Don't forget the packs

Where the difference between good and very good packs can really be seen is when the setup has little headroom. In this situation the esc does not have anything left to give at the end of a flight so head speed is entirely determined by the packs ability to hold a high, loaded voltage. The better packs do not drop as much. This allows you to gear for less headroom which lowers the peak current levels and results in everything running cooler. In effect, the packs are providing the extra headroom to maintain the head speed. If your packs don’t have enough head room then the system needs to be loaded more (either gearing or KV) to provide the headroom.

Danny

Danny - DemonAero Support Team

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01-02-2010 05:02 AM  7 years agoPost 39
Dr.Ben

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Richmond, VA, USA

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Danny,

I think most of what I'm seeing is a function of packs. I'm intentionally not using premium packs because doing so would preclude me from be able to do this in the first place (speaking of competing). Since the temps I've seen so far in the ESC and packs have been quite modest, I'm hoping I'll have enough leeway to gear just a bit taller and gain a bit of headroom without having efficiency go to hell.

I have another auto hub with a 93 t gear already mounted. I think I'll put that in in the AM. I can sneak outside and run the model in the yard for long enough to see how it affects the headroom since I already know the logger number for where I am now. The weather is going to be brutal here tomorrow. If I can find just 5-7% more headroom, I should be OK.

Fun, fun.......

Ben

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

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01-02-2010 05:40 AM  7 years agoPost 40
F1 Rocket

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Melbourne, Florida USA

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Ben-

More headroom does not automaticly mean you have shorter runs time but it will stress the esc a bit more. As long as the thing runs smooth and cool with the revised gearing you should be OK. I don't believe it will have much effect on your run times as long as you don't lean into the extra power that will be available in the earler part of the run.

Danny

Danny - DemonAero Support Team

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